Gibson GA-9 closet find

Discussion in 'Amp Central Station' started by King Fan, Jul 11, 2019.

  1. King Fan

    King Fan Friend of Leo's Ad Free Member

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    My buddy just came into this, and I found the schematic below. Not the best-known old Gibby, it seems.

    The paper caps and especially the filter caps gotta be replaced before power up methinks. I know it's 5Y3 rectified with a pentode preamp, SE into *parallel* 6V6s. And a field coil speaker, about which I know bupkis.

    So: Thoughts, experience, info, links? The TV fronts were made ???1954 to '56 or '57? What say you?

    IMG_2459.jpeg IMG_2452.jpeg IMG_2443.jpeg IMG_2447.jpeg ga9 copy.png
     
  2. theprofessor

    theprofessor Friend of Leo's

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    Very cool! An old pentode-preamp, point-to-point Gibson with a field coil speaker. I look forward to seeing what those in the know say about it. I would love to find one of those in a closet!

    This page suggests that the GA-9 was produced between 1954 and 1959. I think it replaced the previous BR-9, which was produced between 1948-1954. I think you're right that this particular iteration of the GA-9 was produced early on in the '54-'59 period. Maybe through '56?

    I can't find anything right away on Gibson amp serial numbers, but if this one on Reverb was dated correctly, and if the number on the control panel is meaningful, then the one you picture above is older than this 1956 one (https://reverb.com/item/4803439-gibson-ga-9-amplifier-1956-tan), with a serial number of 14341. The number on yours above is 14114, but I don't know how much earlier that makes it. 991 of those GA-9s were shipped in 1956.
     
    Last edited: Jul 11, 2019
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  3. boredguy6060

    boredguy6060 Friend of Leo's

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    Very nice catch!
    I love old Gibson Amps, and so does many others. Wally is also a big fan if I remembered right.
    That one looks almost like new!
    Great catch!
    Get it upgraded, you’ll love the sound.
    I’d love to hear it when you do.
     
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  4. D'tar

    D'tar Tele-Afflicted

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    Sweet little amp! Pinning down Gibson amp details can be a real PITA!!!. Cap date codes, tube, speaker and transformer codes are more useful than say...... A serial numbero_O!

    Should be a fun little machine once it's put through a little servicing!!! ON-OFF, input, volume!!! Love it!
     
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  5. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    Pretty standard - just serviced one. Do the normal things and you'll be good to go.

    Mine ended up like this:


    Screen Shot 2019-07-11 at 11.35.55 AM.png
     
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  6. King Fan

    King Fan Friend of Leo's Ad Free Member

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    Thanks Professor, that's impressive, helpful research.

    Yes, although I've seen sites saying Gibson amp serial numbers tended to be sorta random, your find suggests this one may be older than that '56. And my reading says you're likely right about the TV fronts being 1954 thru 1956. They went to other covering and a more narrow panel after that.

    All in all, compared to Fender, Gibson info is seen through a glass, darkly.
     
    Last edited: Jul 11, 2019
  7. King Fan

    King Fan Friend of Leo's Ad Free Member

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    Thanks, it does look clean, I think. And yes, I'm hoping @Wally can have a look!
     
  8. D'tar

    D'tar Tele-Afflicted

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    Wish they would make a 20-10-10 firecracker!
     
  9. King Fan

    King Fan Friend of Leo's Ad Free Member

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    Right on all counts. I couldn't see a date code on the speaker, but we didn't drop the chassis. The back of the PT and the OT hidden down there might have dates for sure. The glass tube codes are rubbed off pretty well -- didn't pull the 6sj7 though. Caps and maybe the pot could yield more info too.
     
  10. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    Exactly - hence that little F&T guy zip tied and siliconed into place :D
     
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  11. King Fan

    King Fan Friend of Leo's Ad Free Member

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    Well sir, that counts as pertinent and timely!!!

    That's a gorgeous restoration, much nicer than the one on YouTube. But so tasty, I'm gonna need a little caption on your pic. The multi cap canister is what? You wouldn't have a few nice sharp closeups would you?
     
  12. D'tar

    D'tar Tele-Afflicted

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    Been there..... Maybe they will catch on when we all seek out these little gems after all the Fenders have been serviced. Who else would buy $10 worth of caps for $40:)
     
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  13. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    As @D'tar hinted at, the firecracker cap was the 10uF/10uF @ 450 cap and the F&T is the 22uF.

    I have no other pics on this one.
     
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  14. Obelisk

    Obelisk Tele-Afflicted

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    Cool score. I have a 59 GA-8 Gibsonette that has a similar power section with a 12AX7 and no field coil speaker. The power section is basically a tweed Champ on steroids. My favorite slide guitar amp ever. When it's ready to be fired up, I bet that GA-9 gets to a similar zone
     
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  15. boredguy6060

    boredguy6060 Friend of Leo's

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    I had an Invader back in the 70’s.
    I replaced both the speakers 10” and 12” with Celestion Alnico’s. It sounded so good both clean and gritty.
    That’s one amp I’d buy back if I found one..but I’m not in the market. I’ve got too many now..but we can dream.
    It was a great amp.
    I didn’t know Jack about amps back then, just enough to replace blown speakers and tubes
     
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  16. King Fan

    King Fan Friend of Leo's Ad Free Member

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    Thanks, like this? I learn something new here every day.

    upload_2019-7-11_10-12-7.png
     
  17. King Fan

    King Fan Friend of Leo's Ad Free Member

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    Yes, thanks, I've heard the GA-9 maybe went to a 12AX7 somewhere around the time it moved out of the TV front.
     
  18. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    That's exactly the one :D

    Does the thing AND looks the vintage part AND comes with a cool little clip.
     
  19. Mike Eskimo

    Mike Eskimo Doctor of Teleocity Ad Free Member

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    If I hadn’t lent out my master Gibson amp book I would check everything out for you.

    It’s got most iterations of everything. And there are literally about three or four different variations of every damn Amp they made
     
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  20. King Fan

    King Fan Friend of Leo's Ad Free Member

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    Yeah, I've read they changed the actual circuitry 10x more often than even Fender did, and updated the schematics even less often. And their model numbers? Wow.
     
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